The Lyoko Switch Up
by BodySwitchFan
Summary: Summary; You all know the story of when Odd and Yumi switched bodies, well what if instead of it being Odd what if it was Ulrich who had switched with Yumi. Tune in to see how these two manage to live the life and in the body of their respective crushes.
1. Chapter 1

The Lyoko Switch Up

Disclaimer; I do not own anything related to Code Lyoko, all credit goes to Thomas Romain and Tania Palumbo, and the production group MoonScoop Group.

Summary; You all know the story of when Odd and Yumi switched bodies, well what if instead of it being Odd what if it was Ulrich who had switched with Yumi. Tune in to see how these two manage to live the life and in the body of their respective crushes.

A/N; Based on the episode "A Fine Mess" but with some differences being added in. Also when you see Yumi(U) that indicates Ulrich in Yumi's body, and when you see Ulrich(Y) that means it is Yumi in Ulrich's body.

Chapter 1

On a Thursday afternoon once classes were over with, we once again find our heroes fighting against the evil forces of Xana on the digital realm known as Lyoko in the ice sector. Manning the controls at the super computer was the blonde haired resident genius of the group Jeremie Belpois. While his fellow blonde named Odd Della Robbia who has a bit of purple in his hair, was down in the scanner room after being de-virtualized.

Thus leaving the rest of the group which consisted of Yumi Ishiyama the black haired girl, Aelita Schaeffer the pink haired girl, and Ulrich Stern the brown haired male to finish the job. And amongst the group of friends it is known that both Yumi and Ulrich have feelings for each other though both are rather oblivious to how the other feels. Even with talks of encouragement from their friends, neither teen has gained the courage to talk and admit their feelings to each other.

* * *

 **Scene Change**

Currently on Lyoko we find Ulrich, Yumi, and Aelita racing towards the activated tower, while dodging and fighting Xana's monsters. After having Odd be de-virtualized did both Yumi and Ulrich knew that they needed to hurry, and get Aelita safely to the tower in order to deactivate it.

After getting Aelita safely to the tower, and seeing her enter it in order to do her thing did both Ulrich and Yumi come face-to-face with an mega tank. Which is one of the harder monsters to beat. As it was a big ball shaped creature capable of opening and closing itself thus creating a solid defense to hide itself from attacks. As well as being able to fire off a laser wall attack while being in its open position.

Knowing the strength of this creature, and as well as being aware of being low on health points did Ulrich and Yumi take up battle stances, knowing that they had to finish the mega tank off fast by hitting it right in the center of the lyoko symbol. As they got ready for battle Ulrich took out his katana that was apart of his lyoko avatar, and while Yumi readied her battle fans which were also apart of her avatar. Only then did a second mega tank show up evening the odds. Though before either teen could make a move did both mega tanks fired off their attacks , resulting in Yumi and Ulrich being de-virtualized. Although being unaware of the situation that was about to unfold, when they appeared back in the scanner room.

* * *

 **Scene Change**

Sitting on the floor of the scanner room awaiting the safe return of his friends, was the food obsessed and purple loving fanatic Odd Della Robbia. Finding himself feeling both bored and a bit sad at being de-virtualized as his cat avatar on lyoko, did Odd thought to himself " _I wonder if the rest of the gang was able to get to the tower in time, and were able to deactivate it?"_ were the blonde's thoughts. Getting fed up with being bored did Odd come up with a game to pass the time. Thinking to himself " _I should bet on who comes out of the scanner first, if Yumi arrives first then I will get seconds at dinner, but if Ulrich arrives first then I will get thirds"_ feeling happy with the game he invented did Odd eagerly await the arrivals of his friends.

Though Odd did not have to wait too long, as both scanners opened up at the same time revealing both Ulrich and Yumi. Though to the blonde it appeared that both of his friends had a rather tough de-virtualization, as they appeared to be both more than a little woozy and as well as having their eyes closed. Showing concern for his friends did Odd finally speak saying " _hey Yumi and Ulrich are the both of you alright, or do I need to get Jeremie down here to examine you two"_ stated the now worried Odd.

Hearing the call of concern coming from Odd, did Yumi(U) slowly opened up her eyes, and quickly found her balance after the rather brutal de-virtualization that had happened. Feeling a bit better did Yumi(U) finally answer Odd's question " _Yes Odd we are both fine, considering we just got blasted by two mega tanks"_ was her reply. Though after replying did Yumi(U) finally realize a startling realization, in that her voice was not her usual male voice, but was now not only softer and higher in tone but also held a distinct feminine quality to it.

After realizing that her voice was not her own, did Yumi(U) realize that her whole body was not her own. Noticing first her sudden increase in height, as well as feeling her hair tickling the back of her neck which was not right considering she had short hair. Then she looked down and saw two large lumps, that were pushing out the front of the black sweater she now found herself wearing. Going further down did she see that the sweater ended a bit above her belly button showing off a bit of her stomach. Past that did she now see her new legs encased in tight black skinny jeans, and her feet were in black boots. Though the real shocker came when she realized that she no longer held a certain male appendage between her legs after squeezing her thighs together. And finally did she notice that her butt had gotten larger as well.

Quickly putting the pieces together did Yumi(U) realize that somehow she ended up in the body of Yumi Ishiyama. Trying not to panic did Yumi(U) respond to Odd saying " _Odd I know that I may look like Yumi, but you have to believe me when I say that I am really Ulrich in her body"_ she stated to Odd. Though not quite believing it did Odd ask another question " _if you really are Ulrich then name something, that only Ulrich would know about me?"_ questioned Odd to Yumi(U). Thinking of a quick reply did Yumi(U) say " _at night after you take off your shoes, does a smell more powerful then your laser arrows come from them"_ she said to Odd.

Embarrassed by having his stinky feet situation revealed did Odd finally believe what Yumi(U) was saying. Although he did ask her " _how could this have happened?"_ Odd said. Offering her reply Yumi(U) stated " _I do not how how this happened, but first we must check on Yumi in my body then we can go ask Jeremie for answers"_ she said to Odd.

Before both of them had rushed over to Ulrich(Y) who was slowly opening his eyes. After Ulrich(Y) had opened his eyes that first thing he saw on his left side was Odd, though switching over to the right side did Ulrich(Y), come face-to-face with himself. Thinking that this was another ploy of Xana's did Ulrich(Y) confront his double, by saying " _who are you? and why do you look like me?, are you another copy of me made by Xana?"_ were the questions of Ulrich(Y).

Only that is when Ulrich(Y) heard his new voice. Which was now lower in pitch and deeper in tone, totally different from his original voice. Ater which did Ulrich(Y) quickly inspect his body. Noticing his sudden decrease in height, as well as the absence of hair at the back of his neck. Then quickly looking down did he notice the distinct lack of breasts, and the clothing he was wearing which was an open green button shirt over a brown t-shirt. Then noticing his new legs which were now encased in loose fitting cargo pants, and his feet which were now in sneakers instead of the boots he would normally wear. Last but not least did Ulrich(Y) now notice that he had a new appendage in between his legs. After that did Ulrich(Y) realize that he now somehow ended up in the body of Ulrich Stern.

Looking over at his double after the brief inspection of his new body. Did Ulrich(Y) ask " _is that you Ulrich, are you in my body, and did we really switch bodies?"_ towards YumI(U) who responded with " _yes Yumi it is me Ulrich in your body, and yes we did switch bodies though I am not sure how it happened"_ stated Yumi(U). After the last sentence was said did the reality of the situation hit them. Thus resulting in the swapped teens screaming away all their pent up horror and panic.


	2. Chapter 2

Chapter 2

While watching his friends scream their heads off after realizing that they had swapped bodies, did Odd barely notice his cell phone was ringing. Quickly pulling the device from his pants pocket did Odd notice that it was Jeremie calling. Pushing the accept button and bringing the phone to his ear, Odd then heard his fellow blonde's voice asking him " _hey Odd what is taking you guys so long down there?, and is Aelita with you cause she has just deactivated the tower"_ Jeremie had asked Odd.

Casting a quick glance over at the swapped pair, who by now Odd realized had quieted down during his talk with Jeremie. Not sure how to explain the situation before him did Odd utter " _no Aelita is not here yet, and there is a problem between between Yumi and Ulrich that is why we're taking so long"_ was his response to Jeremie. Feeling both confused and concerned for his friends did Jeremie say back " _make sure to grab Aelita after she has re-virtualized, and then make your way back to the control room so you can explain what has happened"_ to Odd before he had hung up.

Although the trio did not have to wait for too long. Soon after the call ended did the Aelita appear safely back in her scanner. After quickly explaining to her that they needed to get to Jeremie fast. Did the four of them make their way to the elevator in order to ride up to the control room.

* * *

 **Scene Change**

After a rather quick and silent elevator ride, during which neither Yumi(U) nor Ulrich(Y) could look at each other still being a bit freaked out with the situation at hand. Did the gang of four finally reach the control room, and headed straight towards Jeremie. After seeing his friends arrive did the blonde haired genius spoke to Odd " _all right Odd time for you to spill the beans, what exactly has happened between Yumi and Ulrich back down in the scanner room?"_ were Jeremie's questions.

Thinking about his reply Odd then spoke saying " _after being de-virtualized, it seems as though both Yumi and Ulrich have somehow swapped bodies"_ was the blunt response from Odd to Jeremie. Resulting in shocking both Jeremie and Aelita speechless, though before either could speak Odd spoke up once again " _and before you ask, yes I did make sure to confirm that they are who they say they are"_ before he had fallen silent.

Rushing over to the super computer, and pounding on various keys did Jeremie also confirm what Odd had stated. Turning around to face his friends did Jeremie finally speak " _it seems that a bug within the materialization program was the cause of the swap between the both of you Yumi and Ulrich"_ Jeremie said to the swapped pair. Though before either of the switched teens could reply, Jeremie also had bad news as well " _normally this would not be a problem for me to fix, but alas it seems that Xana has also discovered the bug as well, and is currently strengthening it meaning that it could take days before I can switch the both of you back"_ did Jeremie reveal to both Yumi(U) and Ulrich(Y).

Feeling dismayed at the fact that they would be stuck in each other's bodies for the foreseeable future, did the swapped pair say to Jeremie " _thanks for the info Jeremie just do your best and we will hang in there, although for now we believe it would be best if everyone starts calling us as our_ _new names in order to avoid confusion and suspicion amongst the students and staff back at school"_ stated both Yumi(U) and Ulrich(Y) to their friends.

After seeing the nods of agreement did the switched teens along with Odd prepared to leave the factory. Though before they could Aelita had stopped them and said to both Yumi(U) and Ulrich(Y) " _don't worry you two I will be helping Jeremie fix the bug, just make sure to be careful and safe"_ she stated before the trio had departed.

* * *

 **Scene Change**

After exiting the factory and making their way through the pipeline, the trio eventually made it back to the manhole cover near their school's campus. Sensing that both Yumi(U) and Ulrich(Y) had some stuff to talk about, did Odd speak up " _well I will see the two of you later, I am going to go get some food"_ he said before leaving the swapped teens behind.

Seeing their friend leave them behind, had brought in an awkward silence between the both of them. Clearing his new throat after a few seconds did Ulrich(Y) eventually speak " _well Yumi as he had remembered to stick to the plan regarding their names, if you have any questions about anything now would be good to voice them"_ he stated to Yumi(U).

Thinking to herself if she had any questions to ask, did Yumi(U) notice that something was itching at her back underneath the sweater she now wore. While scratching at the itch did Yumi(U) voice her thoughts " _well Ulrich right now something seems to be itching me in my back, do you happen to know what it is?"_ she had asked Ulrich(Y). After hearing the question did a furious blush appear on Ulrich(Y)'s face, as he tried to utter out a response.

Finally calming down though still with the blush on his face. Did Ulrich(Y) was finally able to speak " _well you see Yumi that itching sensation, happens to be the strap to your bra that you are currently wearing"_ as he answered the question asked by Yumi(U). After hearing the response given also caused Yumi(U) to blush, at the mention of the undergarment she now finds herself wearing.

While waiting for their blushes to subside Yumi(U) spoke up " _should we come up with some ground rules for our bodies"_ she asked. Taking some time to think about it Ulrich(Y) replied " _no that won't do since this could take days to fix, so we just go on ahead with using the bathroom and bathing routines besides I trust you Yumi with my body"_ he stated to Yumi(U). Touched by the honesty and trust from Ulrich(Y) did Yumi(U) say the same statement back.

Thinking quickly Yumi(U) than asked Ulrich(Y) " _umm Ulrich could you possibly walk me home since I don't know the way there"_ she asked. Replying quickly Ulrich(Y) said " _sure Yumi it is no problem, oh and by the way my pajamas are in my dresser in my room"_ he told Yumi(U). Thankful for the info Yumi(U) said " _thanks Ulrich and make sure to find Odd before curfew so he can show you to our dorm, and my pajamas are just a tank top and boxers"_ to the now once again blushin Ulrich(Y).

After that was said and done did the swapped pair of teenagers depart from Kadic Academy, to get to Yumi's house in order to drop off Yumi(U).


	3. Chapter 3

Chapter 3

While walking towards the Ishiyama residence was an experience in itself for both Yumi(U) and Ulrich(Y). During the walk the both of them could not help, but take note of the different ways their new bodies moved while walking. Which once again reminded them of their current situation.

Showing Yumi(U) the way to her new home for now during the walk, Ulrich(Y) took notice of the way his new body moved. From the straightforward and stiff movements in his new hips, to the lack of bouncing on his chest due to the lack of breasts, and finally the lack of a swaying motion from his new butt, as well as the absent feeling of hair due to having shorter hair now. After taking note of all these different sensations, did Ulrich(Y) think to himself " _wow a guy's body sure does move differently, then that of a girl's body"_ as he and Yumi(U) continued their walk.

On the other hand though, Yumi(U) was also taking notice of the way her new body moves as well. First off she noticed how there was a gentle sway within her new hips, then she noticed the swaying motion of her new butt, and then did she finally notice the gentle rhythmic bouncing of her new breasts. After taking of all this did Yumi(U) think to herself " _wow I never really noticed how every part of a girl's body moves while walking"_ were her inner thoughts.

Though speaking of her new chest region did Yumi(U) once again notice, how the bra she was wearing was both annoying and irritating her. Seeing the annoyed look on his former face did Ulrich(Y) chuckle before saying " _is the bra still bugging you there Yumi?"_ he had asked Yumi(U). Scratching at her back once more did Yumi(U) reply " _yes it is Ulrich the straps are still itching me, and they are also digging into my shoulders a bit"_ to the still chuckling Ulrich(Y). Once done chuckling did Ulrich(Y) say " _yea that does get annoying, but don't worry once you get into my room you can take it off"_ to Yumi(U) who was still scratching her back.

After quite a long walk, did the swapped teens finally reach the Ishiyama residence. Although before Yumi(U) could enter did Ulrich(Y) spoke up saying " _oh by the way Yumi if you use the restroom make sure you sit down, and wipe front to back after you're done"_ to the now shocked and embarrassed Yumi(U). Though still embarrassed did Yumi(U) offer a quick comeback " _well Ulrich speaking of using the restroom, do make sure you hold a certain appendage correctly or else you'll have one big mess to clean"_ thus now shocking and embarrassing Ulrich (Y) as well. When that was said and done did Yumi(U) enter her new home, and Ulrich(Y) leave back Kadic after bidding each other goodbye and a goodnight.

* * *

 **Scene Change**

Quickly getting back to Kadic Academy before dusk had fallen, did Ulrich(Y) go search for Odd. Finding his friend and new roommate by the cafeteria Ulrich(Y) noticed that Odd had some slap marks on both of his cheeks. Raising an eyebrow Ulrich(Y) asked " _what in the world had happened to you Odd?"_ was the question asked. Still feeling the sting from the slaps did Odd reply " _well these two girls found out that I was dating the both of them, and as you can see they did not take it very well"_ to Ulrich(Y) who was shaking his head in disappointment. After seeing and hearing the punishment of his friend did Ulrich(Y) say " _alright Odd now since that is done with, let's get heading back to the dorm before Jim catches us"_ to the still hurting and embarrassed blonde.

Getting to their dorm room was easy enough, though now came the part that Ulrich(Y) was not looking forward to. Realizing that his new bladder was now full, did Ulrich(Y) slowly find himself facing the toilet. Deciding to get it over and done with he quickly undid his pants and pulled down his underwear, though seeing his new penis for the first time stuns Ulrich(Y) into silence. Quickly shaking his head to clear away his thoughts, did Ulrich(Y) grab hold of his new equipment and aimed towards the toilet, and released the stream of urine into the bowl and flushed afterwards. After redoing his pants and washing his hands, did Ulrich(Y) strip down to a tank top and boxers before climbing into his new bed, and pulling the covers over himself.

* * *

 **Scene Change**

After the embarrassing bathroom talk and seeing Ulrich(Y) leave, did Yumi(U) finally enter her new home. Only to be quickly greeted by her new mother saying " _oh Yumi dear it is good to see you home, now come and sit down dinner is just about ready oh but don't forget to wash your hands"_ which Yumi(U) did. Sitting down at the table after washing her hands, was Yumi(U) treated to a traditional japanese dinner. Thankfully having little to no trouble with using chopsticks, was Yumi(U) able to make it past dinner with her new family.

Finishing her meal and putting her dishes in the sink, did Yumi(U) ask " _mother and father is it alright if I may be excused to my room now?"_ to her new parents. Seeing them nod okay did Yumi(U) went upstairs to her room. Finding her new room easily since there was only three rooms upstairs, and knowing that Hiroki was already in his room did Yumi(U) enter the one across from it. Once she had entered and shut the door behind her, did Yumi(U) see that the room was perfectly suited for her. Though that was when Yumi(U) had realized that her new bladder was full, telling her that she needed to use the toilet.

Finding out that her new room cam with a private bathroom, was a welcomed relief to Yumi(U). Quickly entering and shutting the door did Yumi(U) turn around, and came face-to-face with the toilet, before blushing at what she was about to do. Shaking her head to try and get the blush to fade, did Yumi(U) unbuttoned and unzipped her pants thus seeing the black panties she was wearing. Taking a deep breath and relaxing did Yumi(U) finally pull down her underwear, and turned around to sit on the toilet. After which she relaxed and had let the urine flow out of her new vagina. Though after she was done did Yumi(U) remembered Ulrich(Y)'s words, after getting some toilet paper did she guided her hand towards her new crotch and wiped front to back as she was instructed.

Once she was done wiping and had dropped the paper in the toilet did Yumi(U) flush the toilet. After she had flushed and pulled up her underwear and redid her pants, did Yumi(U) walk back into her room after washing her hands. After taking a quick glance around her new room, Yumi(U) once again felt her bra irritating her.

Finally getting tired of wearing the irritating undergarment, did Yumi(U) go to remove it. Heading over to the standing mirror and seeing her reflection did Yumi(U) move to take off her sweater. Once it was off did Yumi(U) see the upper half of her body topless, except for the lacy black bra she was wearing. Before she removed her bra did Yumi(U) also remove her boots, socks, and pants thus leaving her wearing her bra and panties. Then did Yumi(U) move her hands to the back of the bra to unhook it, although the struggle to unhook the bra was apparent. Thinking to herself " _how in the world do girls do this everyday"_ as Yumi(U) continued to struggle with her bra clasp, finally after some time had passed did the clasp finally come undone. Feeling the bra come loose did Yumi(U) breathe a sigh of relief.

Though Yumi(U) blushed hard when she realized that the next step was to take off the bra. Slowly pulling the straps down her shoulders did Yumi(U) feel her heart begin to beat faster. Finally after pulling the straps off and letting the bra fall to the floor, did Yumi(U)'s eyes go wide staring at two perfectly sized b-cup pale breasts topped with two cute and perky pink colored nipples. After tearing her gaze away from the mirror did Yumi(U) go back to the dresser in search of her pajamas. Finding a white tank top and red sweatpants, did Yumi(U) put them on and climbed into her new bed and under the covers.

Finally after a long tiring, stressing, and confusing day did the swapped teenagers fall asleep.


End file.
